225 ILCS 705/19.11

There shall be at least two travelable passageways, to be designated as escape ways, from each working section to the surface whether the mine openings are shafts, slopes, or drifts. At least one of these passageways must be equipped with a lifeline cord. Escape ways shall be kept in safe condition for travel and reasonably free from standing water and other obstructions. One of the designated escape ways may be the haulage road. One of the escape ways shall be ventilated with intake air. At mines now operating with only one free passageway to the surface, immediate action shall be taken to provide a second passageway. The return air passageway to the surface must be marked with reflectors or other appropriate signage, as approved by the Department.